EAST RUTHERFORD, N.J. — Giants General Manager Dave Gettleman gave a rousing endorsement of Coach Pat Shurmur, stood behind his decision to draft running back Saquon Barkley and laughed off suggestions that the team might trade receiver Odell Beckham Jr.

But Gettleman, in his first news conference with reporters since the summer, remained surprisingly noncommittal on Wednesday about quarterback Eli Manning’s future with the Giants, leaving the door open for the organization to potentially move on from its two-time Super Bowl most valuable player this off-season.

“We will do what’s in the best interest of the New York Giants,” Gettleman said, before adding: “What we’re trying to do here is build sustained success. That takes some brutal honesty, and it takes some tough decisions.”

Gettleman said he and Manning had met for an “extensive” conversation on Monday that he deemed to be “very honest and upfront.” Notably, it was Manning who initiated the discussion.

“Eli came in and wanted to talk,” Gettleman said. “It wasn’t like he was called to the principal’s office; he came to see me.”

Manning, who turns 38 on Thursday and is under contract through the 2019 season, started all 16 games for the Giants this season and threw for 4,299 yards with 21 touchdowns and 11 interceptions. He completed 66 percent of his passes, a career high, and finished with a 92.4 quarterback rating, his highest since 2015.

But the Giants started with a 1-7 record this season before finishing 5-11, and they have an 8-23 record over the past two years with Manning as the starter. There are questions about his pocket presence, decision-making and arm strength — including from Beckham, who criticized Manning in an interview with ESPN in October.

Gettleman pointed to the offense’s productivity in December, when the Giants scored 30, 40, 27 and 35 points (they also were shut out by the Tennessee Titans on Dec. 16).

“He still can make N.F.L. throws,” Gettleman said of Manning. “He’s still got it.”

Shurmur shares that opinion, having defended Manning throughout the season — and especially in recent weeks regarding the quarterback’s ability to return as the Giants’ starter in 2019. On Monday, he said Manning should be evaluated based on his performance in the second half of the season.

“I think he was better able to showcase what he could do once we solidified the offensive line,” Shurmur said. “I think that’s a fair assessment.”

As for how he planned to assess Manning’s performance amid the swings in fortune throughout the season, Gettleman was less effusive. He said he would watch film “until my eyes bleed.”

Manning has a full no-trade clause, and cutting him would incur a sizable hit to the Giants’ salary cap. Nevertheless, Gettleman said, “everything is on the table for us.”

Gettleman executed an extensive roster overhaul this season, his first as the team’s general manager. But the Giants still finished last in the N.F.C. East, leaving them with the No. 6 overall pick in the coming draft.

This year’s class is not expected to contain the same caliber of quarterback prospects as last year, when the quarterbacks Baker Mayfield, Sam Darnold, Josh Rosen and Josh Allen all went in the first 10 slots of the draft. Still, Gettleman defended his decision to draft Barkley, a running back, with the second overall pick in 2018. Barkley ran for 1,307 yards, a Giants rookie record, and added 721 yards receiving.

“If I was in that situation 100 times, I’d draft him 100 times,” Gettleman said of Barkley.

His assessment of the 2019 draft options remained the same as a year ago, he said, but he did not rule out selecting a quarterback. The Giants did select a quarterback in the fourth round last summer, Kyle Lauletta, who struggled in his lone appearance of the season, going 0 for 5 with one interception during the second half against Washington on Dec. 9.

“You’re going to take the best player available,” Gettleman said. “You start reaching, you’re going to get in trouble.”

The Giants played the final four games of the season without Beckham, who was sidelined with a quadriceps injury. Even though the Giants’ offense produced without Beckham, Gettleman quickly refuted any notion that the team might look to trade the star receiver, who signed a five-year, $90 million contract extension in August.

“We didn’t sign him to trade him,” Gettleman said.

Gettleman praised Shurmur’s steadiness after the team’s abysmal start, and he was pleased with the effort the team gave down the stretch, especially after being eliminated from playoff contention.

“We’re not happy with 5-11, nobody is,” Gettleman said. “But I feel good about where we’re headed.”

A version of this article appears in print on , on Page B9 of the New York edition with the headline: Manning’s Future Suddenly Seems Murky. Order Reprints | Today’s Paper | Subscribe